package BlogHashBuck;

public class BlogHashBuck2<K,V> {
    static class Node<K,V> {
        public K key;
        public V value;
        public Node<K, V> next;

        public Node(K key, V val) {
            this.key = key;
            this.value = val;
        }
    }

    public Node<K,V>[] array=(Node<K,V>[])new Node[10];
    public int usedSize;
    public static double loadFactor=0.75;

    public void put(K key,V value){
        int hash=key.hashCode();
        int index=hash% array.length;
        Node<K,V> cur=array[index];
        while(cur!=null) {
            if(cur.key.equals(key)){
                cur.value=value;
                return;
            }
            cur=cur.next;
        }

        Node<K,V> node=new Node<>(key,value);
        node.next=array[index];
        array[index]=node;
        usedSize++;
        if(getLoadFactor()>=loadFactor) {
            reSize();
        }
    }

    private double getLoadFactor(){
        return usedSize*1.0/array.length;
    }

    private void reSize() {
        Node<K,V>[] newArray=(Node<K,V>[])new Node[array.length*2];
        for(int i=0;i<array.length;i++) {
            Node<K,V> cur=array[i];
            while(cur!=null) {
                int hash=cur.key.hashCode();
                int newIndex=hash%newArray.length;
                Node<K,V> curN=cur.next;
                cur.next=newArray[newIndex];
                newArray[newIndex]=cur;
                cur=curN;
            }
        }
        array=newArray;
    }

    public V get(K key) {
        int hash=key.hashCode();
        int index=hash% array.length;
        Node<K,V> cur=array[index];
        while(cur!=null) {
            if(cur.key.equals(key)){
                return cur.value;
            }
            cur=cur.next;
        }
        return null;
    }

}
